Adjustable electrode transporter for lateral electrode spacing during electroplating



July 5, 1969 G. E. M. GEILERT 3,

ADJUSTABLE ELECTRODE TRANSPORTER FOR LATERAL ELECTRODE SPACING DURING ELECTROPLATING Filed Nov. 25, 1966 2 Sheets-Sheet 1 PROGRAMMED l3 CONTROL OVERHEAD RAH.

CATHODE TRANSPORTER M A M A v ELECTRiFIED NON-ELECTRIFIED TANK TANK FIG.2

INVENTOR.

MQI'BiWM VW 5, 1969 G. E. M. GEILERT 3,455,309

ADJUSTABLE ELECTRODE TRANSPORTER FOR LATERAL ELECTRODE SPACING DURING ELEGTROPLATING Filed NOV. 25, 1966 2 Sheets-Sheet 2 o O 73 1 l 36 INVENTOR.

' MMWI W I"! ll II II" llll IHI IHHI United States Patent 3,455,809 ADJUSTABLE ELECTRODE TRANSPORTER FOR LATERAL ELECTRODE SPACING DURING ELECTROPLATING Georg Erick Max Geilert, Solingen, Germany, assignor to Baker Bros. Inc., Canton, Mass., a corporation of Massachusetts Filed Nov. 25, 1966, Ser. No. 596,863 Int. Cl. C23b /70; B65g 49/04; B01k 3/00 US. Cl. 204-198 5 Claims The present invention relates in gener'al to electroplating and more particularly concerns a novel electromechanical device mounted on a programmed transporter, or hoist system, facilitating varied distances between two cathode bars in a direction transverse to the direction of transport from electrified tank to nonelectrified tanks to achieve optimum spacing between cathode and anode electrodes during electroplating while minimizing the width of tanks in which the cathodes are immersed following the electroplating process.

According to the invention, there is transporter means for supporting the cathode supports and means 'for guiding the transporter means along a prescribed path above a cascade of at least one electrified tank, in which plating occurs, and at least one nonelectrified tank. The transporter means supports cathode support means arranged to support at least two cathode bars substantially parallel to said prescribed path. The cathode support means includes means for continuously varying the spacing between the parallel cathode bars so that optimum spacing is achieved between the respective cathode bars and adjacent anodes in the electrified tank while minimizing the separation between cathode bars when in a nonelectrified tank.

Electroplating automatic techniques in which parts to be electroplated are transported from an electrified tank to a non-electrified tank are well known in the art, and Davis Patent No. 2,650,600 is an example of such a system known in the art as a fixed, or classic, automatic system. That patent discloses conveying parts from one bath to another and changing the spacing between successive parts along the line of movement when changing from electrified to nonelectrified tanks. Although that system may function well for plating specific parts, it lacks flexibility for plating a wide variety of parts of different sizes and where difierent optimum spacings are required dependent upon the specific material being plated, the plating material, the plating solution, the thickness of the plating and perhaps other factors.

Accordingly, it is an important object of this invention to provide an automatic plating system of exceptional flexibility for allowing maintenance of optimum spacing between anodes and cathodes for plating a wide variety of objects of a wide variety of materials in a Wide variety of plating solutions to achieve a wide variety of plating thicknesses.

It is a further object of the invention to achieve the preceding object while also minimizing the spacing between cathodes when immersed in nonelectrified tanks to minimize the volume of such tanks, the space they occupy and the volume of solution required in such tanks.

It is a further object of the invention to achieve the 3,455,809 Patented July 15, 1969 preceding objects with a system especially adapted for programmed control.

Numerous other features, objects and advantages of the invention will become apparent from the following specification when read in connection with the accompanying drawing in which:

FIG. 1 is a block diagram illustrating the logical arrangement of a system according to the invention;

FIG. 2 is a diagrammatic representation of (1) two cathodes disposed between three anodes with optimum spacing therebetween in an electrified tank, (2) how the cathodes would fit in a nonelectrified tank of minimum width following transfer from the electrified tank of FIG. 2 with the spacing between cathodes remaining the same, and (3) the cathodes in a nonelectrified tank of minimum size when the spacing between cathodes is reoriented in accordance with the invention;

FIG. 3 is a perspective view of an electromechanical device according to the invention mounted on a programmed transporter; and

FIG. 4 is a closeup perspective view of the support for the ends of a pair of cathodes showing the specific mechanism for controlling the spacing therebetween in an exemplary embodiment of the invention.

With reference now to the drawing and more particularly FIG. 1 thereof, there is shown a diagrammatic representation of an electroplating system incorporating the principles of the invention. A cathode transporter 11 rides on an overhead rail 12. In response to appropriate control signals from programmed control means 13 cathode transporter 11 immerses and withdraws typically two cathode bars, which cathode bars may support electrically contacting conductive elements to be plated, into and from electrified tank 14 first with optimum spacing for the particular plating operation, and then into and from nonelectrified tank 15 with reduced spacing between cathodes so that nonelectrified tank 15 may be much narrower than electrified tank 14.

The advantages of the invention will be better understood from the top view of electrified tank 14 and nonelectrified tank 15 diagrammatically represented in FIG. 2. Electrified tank 14 for plating is shown with two cathode bars 16 and 17 alternating with three anode bars 21, 22 and 23. A typical separation in the electrified tank, S for proper plating is 26 inches. Good plating practice requires three anode rods in a tank where two cathode nods are used with a typical width of the electrified plating tank, W being 54 inches. If conventional techniques were followed and the spacing of cathode bars 16 and 17 unaltered when transferring them from electrified tank 14 t0 nonelectrified tank 15, the width of the nonelectrified tank, W' would have to be of the order of 38 inches, allowing at least 6 inches on each side of the cathode bars for the movement of parts hung on the cathode. However in accordance with the principles of the invention, when cathode transporter 11 indexes from electrified tank 14 to nonelectrified tank 15, cathode bars 16 and 17 are moved toward each other. Since there is no longer any cathode to anode spacing requirement, the limiting factor on the spacing, S in the nonelectrified tank 15 is the six inches on either side of the cathode bars for accommodating the parts. The nonelectrified tank width, W is then only of the order of 24 inches, a reduction in width, volume and fluid requirements of more than one-third. Since in a typical electrode plating line the ratio of the number of nonelectrified tanks to electrified tanks may be anywhere from 90:1 to 1, the reduction in size of nonelectrified tanks achieved by practicing the invention represents a considerable saving in the initial cost of tanks as well as the required area to perform a wide variety of plating operations.

Referring to FIG. 3, there is a perspective view of cathode transporter 11 suspended from overhead rail 12. The cathode transporter 11 specifically illustrated actually supports two pairs of cathodes from a first cathode pair support means 24 and a second cathode pair support means 25. Each of the supports 24 and 25 are suspended from a yoke, such as 26, having a pair of flanged wheels, such as 27 that are driven by a motor, such as 31 to control the positioning of supports 24 and 25 relative to overhead rail 12 by movement along transverse I beam 32 which in turn is supported for translation along overhead rail 12 by any suitable well known means. Supports 24 and 25 have end pairs of depending vertical members such as 34 and 35 of support 24 and 36 and 37 of support 25. Each of these vertical members carry a respective pair of cathode bar end supports 41, 42, 43 and 44, respectively. Each of these members may be positioned vertically by vertical positioning motors such as 45 and 46.

Referring to FIG. 4, there is shown a closeup of cathode bar end supports 44, supports 41, 42 and 43 being the same. There is a left support 51 and a right support 52 each formed with a pair of channels such as 53 and 54 and 55 and 56, respectively, for accommodating the ends of hangers that in turn support the ends of cathode bars. Each of supports 51 and 52 ride along a lower slide rod 57 and an upper slide rod 58. Rotation of the central left threaded drive shaft 61 and right threaded drive shaft 62 coupled by coupling 63, shafts 61 and 62 having threads of opposite sense, causes supports 51 and 52 to move closer together until inner limit switch 64 is actuated by limit switch tab 65 on support 51 when driving gear 66 rotates in one sense. When driving gear 66 rotates in opposite sense, supports 51 and 52 move apart to the position shown until outer limit switch 67 is actuated by tab 65. The position shown establishes the separation between the cathode bars whose ends are supported in supports 51 and 52 to the separation, S in an electrified tank while the closer together position when limit switch 64 is actuated corresponds to the separation, S in a nonelectrified tank. An electric motor, such as 71 (FIG. 3) actually rotates gear 66, this motor preferably being reversible.

Although the specific means for raising and lowering the cathode bar end supports is not a part of the invention, FIG. 4 shows a specific means for raising and lowering the end supports in a specific embodiment of a system incorporating the invention. A U-shaped girder 72 is attached to support 44 vertically oriented inside the main vertical member 36 surrounding the chain. Girder 72 has a member 73 formed with a channel sufficiently wide to allow the chain to move through the channel but not wide enough to allow the stop 74 to pass through. The lower lip of this member therefore rides on the stop 74 to move up and down with the left section of the chain.

While preferably the apparatus according to the invention is employed in a preprogrammed automatic system, the principles of the invention may be applied semiautomatically or manually. For example, an operator can operate switches to control the raising and lowering of the dilferent supports and initiate the energization of the motors so as to control the relative spacing between cathode bars for electrified and nonelectrified immersion. Alternately, a worker could raise, lower and relatively position the cathode end supports manually. With the specific apparatus illustrated in FIG. 4 the positioning can take place manually by moving gear 66 with a suitable crank.

There has been described novel apparatus and techniques for electroplating which facilitate attaining optimum spacing between a plurality of cathodes in the electrified tank while maintaining minimum spacing between cathodes when the cathodes are lowered into nonelectrified tanks to appreciably reduce the initial cost, the space required and the amount of fluids required for an electroplating operation.

It is evident that those skilled in the art may now make numerous uses and modifications of and departures from the specific apparatus and techniques described herein without departing from the inventive concepts. Consequently, the invention is to be construed as embracing each and every novel feature and novel combination of features present in or possessed by the apparatus and techniques herein disclosed and to be limited solely by the spirit and scope of the appended claims.

What is claimed is:

1. Electroplating apparatus comprising,

first and second cathode support means for supporting first and second generally parallel electrically conductive cathode bars in first and second cathode bar regions defined thereby,

transporter means for supporting said first and second cathode support means,

means for guiding said transporter means along a prescribed path generally parallel to said first and second cathode bar regions and normally above at least one electrified tank in which plating occurs and at least one nonelectrified tank,

means operatively connecting said cathode bars to a source of electric current for electroplating in said electrified tank,

and means for selectively relatively displacing said first and second cathode support means to selectively adjust the spacing between said first and second cathode bar regions in a direction transverse to said path,

whereby optimum spacing may be achieved between the first and second cathode bars when in the first and second cathode regions respectively and immersed in an electrified tank while minimizing the separation therebetween when in a nonelectrified tank.

2. Electroplating apparatus in accordance with claim 1 and further comprising,

said at least one electrified tank of length slightly greater than that of said first and second cathode bar regions for accommodating said regions, and said at least one nonelectrified tank of length slightly greater than that of said first and second cathode bar regions for accommodating said regions,

the width of said at least one electrified tank being greater than that of said at least one nonelectrified tank.

3. Electroplating apparatus in accordance with claim 2 and further comprising at least one anode bar within said electrified tank generally arallel to said path and spaced from said first and second cathode regions by said optimum spacing When the first and second cathode bars are immersed in said electrified tank.

4. Electroplating apparatus in accordance with claim 3 and further comprising second and third anode bars within said electrified tank generally parallel to said path and spaced from a respective one of said first and second cathode regions by said optimum spacing when the first and second cathode bars are immersed in said electrified tank.

5. Electroplating apparatus in accordance with claim 4 wherein the width of said at least one electrified tank corresponds to substantially the span embraced by said second and third anode bars and the width of said at least one nonelectrified tank corresponds substantially to four times the distance between a cathode bar and the edge 6 of a part carried by the cathode bar for plating that is 2,588,910 3/1952 Davis 204198 furthest from the cathode bar, 2,591,682 4/ 1952 Davis 204198 XR whereby the first and second cathode bars with parts 3,276,985 10/1966 Laney 204-297 XR that have been electroplated may freely move int and from said at least one nonelectrified tank While JQHN MACK, Primary Examiner the Width of the latter tank is substantially the mini- 5 mum to bathe the parts when carried by the first and VALENTINE, ASSlStaHt Xa r second cathode bars and immersed in the latter tank.

US. Cl. X.R. References Cited UNITED STATES PATENTS 2,043,698 6/1936 Dyer 204-202 

1. ELECTROPLATING APPARATUS COMPRISING, FIRST AND SECOND CATHODE SUPPORT MEANS FOR SUPPORTING FIRST AND SECOND GENERALLY PARALLEL ELECTRICALLY CONDUCTIVE CATHODE BARS IN FIRS AND SECOND CATHODE BAR REGIONS DEFINED THEREBY, TRANSPORTER MEANS FOR SUPPORTING SAID FIRST AND SECOND CATHODE SUPPORT MEANS, MEANS FOR GUIDING SAID TRANSPORTER MEANS ALONG A PRESCRIBED PATH GENERALLY PARALLEL TO SAID FIRST AND SECOND CATHODE BAR REGIONS AND NORMALLY ABOVE AT LEAST ONE ELECTRIFIED TANK IN WHICH PLATING OCCURS AND AT LEAST ONE NONELECTRIFIED TANK, MEANS OPERATIVELY CONNECTING SAID CATHODE BARS TO A SOURCE OF ELECTRIC CURRENT FOR ELECTROPLATING IN SIAD ELECTRIFIED TANK, AND MEANS FOR SELECTIVELY RELATIVELY DISPLACING SAID FIRST AND SECOND CATHODE SUPPORT MEANS TO SELECTIVELY ADJUST THE SPACING BETWEEN SAID FIRST AND SECOND CATHODE BAR REGIONS IN A DIRECTION TRANSVERSE TO SAID PATH, WHEREBY OPTIMUM SPACING MAY BE ACHIEVED BETWEEN THE FIRST AND SECOND CATHODE BARS WHEN IN THE FIRST AND SECOND CATHODE REGIONS RESPECTIVELY AND IMMERSED IN AN ELECTRIFIED TANK WHILE MINIMIZING THE SEPARATION THEREBETWEEN WHEN IN A NONELECTRIFIED TANK. 